The present invention relates to the field of coronary artery disease. More specifically, it relates to detecting with a clinically sufficient degree of diagnostic accuracy whether a human patient from the general population has coronary artery disease (“CAD”) and, if so, to determining with a clinically sufficient degree of diagnostic accuracy which stage of CAD the patient has.
Steinberg D, “Lewis A. Conner Memorial Lecture, Oxidative Modification Of LDL And Atherogenesis,” Circulation 1997, 95: 1062-1071, notes that deaths from coronary heart disease continue to outnumber deaths from any other single cause in the United States. Kolata, “A New Generation Of Tests To Determine Heart Trouble,” New York Times News Service (Nov. 26, 1995), reports that half of the 600,000 Americans who have heart attacks each year have no symptoms beforehand and that as many as 30% of heart disease patients do not have any obvious risk factors such as high blood pressure, high cholesterol levels, diabetes, or a family history of heart disease. (All of the documents mentioned or otherwise referenced herein are incorporated herein in their entireties for all purposes.)
The ability to accurately determine whether a patient has coronary artery disease and, if so, what stage the patient has, has been a long-standing (but heretofore unachieved) goal of medical science. There have been many attempts to provide monoclonal antibodies that recognize in humans and other animals various low density lipoprotein (“LDL”) substances and/or other substances that might be associated with atherosclerosis and/or thrombosis. There have also been attempts to provide methods for determining possible markers for atherosclerosis and coronary injury. See, e.g., U.S. Pat. Nos. 5,024,829, 5,026,537, 5,120,834, 5,196,324, 5,223,410, 5,362,649, 5,380,667, 5,396,886, 5,453,359, 5,487,892, 5,597,726, 5,658,729, 5,690,103, and 5,756,067; EPO Published Application 0 484 863 A1; PCT/EP97/03287 (unpublished application); PCT/EP97/03493 (unpublished application); PCT Published Application WO 94/23302; Adams et al., “Cardiac Troponin I. A Marker With High Specificity For Cardiac Injury,” Circulation 1993; 88(1): 101-106; American Biogenetic Sciences Inc., 1995 Annual Report, 24 pages (1995); American Biogenetic Sciences, Focus on Diagnostic Tests: A Technology Analysis, Updated Full Report, Paisley and Habermas, Inc. (Jun. 3, 1996); Antman et al., “Cardiac-Specific Troponin I Levels To Predict The Risk Of Mortality In Patients With Acute Coronary Syndromes,” N. Eng. J. Med. 1996; 335(18): 1342-1349; AtheroGenics, Inc. Web Site (WWW.ATHEROGENICS.COM); Hamm et al., “Emergency Room Triage Of Patients With Acute Chest Pain By Means Of Rapid Testing For Cardiac Troponin T Or Troponin I,” N. Eng. J. Med. 1997; 337(23): 1648-1653; Hammer et al., “Generation, Characterization, And Histochemical Application Of Monoclonal Antibodies Selectively Recognizing Oxidatively Modified ApoB-Containing Serum Lipoproteins,” Arterioscler. Thromb. Vasc. Biol. 1995; 15(5): 704-713; Hoff et al., “Lesion-Derived Low Density Lipoprotein And Oxidized Low Density Lipoprotein Share A Lability For Aggregation, Leading To Enhanced Macrophage Degradation,” Arterioscler. Thromb. 1991; 11(5): 1209-1222; Hoffmeister et al., “Alterations Of Coagulation And Fibrinolytic And Kallikrein-Kinin Systems In The Acute And Post-Acute Phases In Patients With Unstable Angina Pectoris,” Circulation 1995; 91(10): 2520-2527; Holvoet, Collen, et al., “Stimulation With A Monoclonal Antibody (mAb4E4) Of Scavenger Receptor-Mediated Uptake Of Chemically Modified Low Density Lipoproteins By THP-1-Derived Macrophages Enhances Foam Cell Generation,” J. Clin. Invest. 1994; 93: 89-98; Holvoet and Collen, “β-VLDL Hypercholesterolemia Relative To LDL Hypercholesterolemia Is Associated With Higher Levels Of Oxidized Lipoproteins And A More Rapid Progression Of Coronary Atherosclerosis In Rabbits,” Arterioscler. Thromb. Vasc. Biol. November 1997; 17(11): 2376-2382; Holvoet and Collen, “Oxidized Lipoproteins In Atherosclerosis And Thrombosis,” FASEB J 1994; 8: 1279-1284; Holvoet and Collen, “Malondialdehyde-Modified Low Density Lipoproteins In Patients With Atherosclerotic Disease,” J. Clin. Invest. 1995; 95: 2611-2619; Holvoet, Collen, et al., “Correlation Between Oxidized Low Density Lipoproteins And Von Willebrand Factor In Chronic Renal Failure,” Thromb. Haemost. 1996; 76(5): 663-669; Holvoet, Collen, et al., “Correlation Between Oxidized Low Density Lipoproteins And Coronary Artery Disease In Heart Transplant Patients,”Abstract published in Final Programme of 66th Congress of the European Atherosclerosis Society, Florence (Italy), Jul. 13-14, 1996, Abstract Book, page 47; Holvoet, Collen, et al., “Oxidized Low Density Lipoproteins In Patients With Transplant-Associated Coronary Artery Disease,” Arterioscler. Thromb. Vasc. Biol. January 1998; 18(1): 100-107; Holvoet, Collen, et al., Presentation at 70th Scientific Session Of The American Heart Association, Orlando, Fla., November 9-12, and published in abstract form in Circulation 1997; 96(Suppl. I): I417 (Abstract 2328); Itabe et al., “A Monoclonal Antibody Against Oxidized Lipoprotein Recognizes Foam Cells In Atherosclerotic Lesions: Complex Formation Of Oxidized Phosphatidylcholines And Polypeptides,” J. Biol. Chem. 1994; 269(21): 15274-15279; Itabe et al., “Sensitive Detection Of Oxidatively Modified Low Density Lipoprotein Using A Monoclonal Antibody,” J. Lipid Res. 1996; 37: 45-53; Kolata, “A New Generation Of Tests To Determine Heart Trouble,” New York Times News Service (Nov. 26, 1995); Kotani et al., “Distribution Of Immunoreactive Malondialdehyde-Modified Low-Density Lipoprotein In Human Serum,” Biochimica et Biophysica Acta 1994; 1215: 121-125; Menschikowski et al., “Secretory Group II Phospholipase A2 In Human Atherosclerotic Plaques,” Atherosclerosis 1995; 118:173-181; Muldoon et al., “C-Reactive Protein And Serum Amyloid A Protein In Unstable Angina,” N. Engl. J. Med. 1995; 332(6): 398-400; Ohman et al., “Cardiac Troponin T Levels For Risk Stratification In Acute Myocardial Ischemia,” N. Eng. J. Med. 1996 335(18): 1333-1341; Palinski et al., “Antisera And Monoclonal Antibodies Specific For Epitopes Generated During Oxidative Modification Of Low Density Lipoprotein,” Arteriosclerosis 1990; 10(3): 325-335; Ravalli et al., “Immunohistochemical Demonstration Of 15-Lipoxygenase In Transplant Coronary Artery Disease,” Arterioscler. Thromb. Vasc. Biol. 1995; 15(3): 340-348; Reade et al., “Expression Of Apolipoprotein B Epitopes In Low Density Lipoproteins Of Hemodialyzed Patients,” Kidney Int. 1993; 44: 1360-1365; Reverter et al., “Platelet Activation During Hemodialysis Measured Through Exposure Of P-Selectin: Analysis By Flow Cytometric And Ultrastructural Techniques,” J. Lab. Clin. Med. 1994; 124(1): 79-85; Salonen et al., “Autoantibody Against Oxidised LDL And Progression Of Carotid Atherosclerosis,” Lancet 1992; 339(8798): 883-887; Uchida et al., “Protein-Bound Acrolein: Potential Markers For Oxidative Stress,” Proc. Natl. Acad. Sci. USA 1998; 95: 4882-4887; and Van de Werf, “Cardiac Troponins In Acute Coronary Syndromes,” N. Eng. J. Med. 1996; 335(18): 1388-1389.
However, as noted in the literature, there is no currently available method for determining with a clinically sufficient degree of diagnostic accuracy the presence of coronary artery disease in a patient and, if the disease is present, for distinguishing with a clinically sufficient degree of diagnostic accuracy between or among the non-acute (i.e., chronic) and acute stages of that disease, the non-acute stages being stable angina and presumably asymptomatic coronary artery disease and the acute stages being unstable angina and acute myocardial infarction.
For example, U.S. Pat. No. 5,380,667 (issued Jan. 10, 1995) notes that most individuals with heart disease are largely asymptomatic until their first heart attack, that the major risk factors thus far identified in the prior art are not perfect predictors (particularly for predicting the risk of coronary artery disease in any single individual), and that thirty to forty percent of the population is still misdiagnosed using the known major risk factors (column 1, lines 31-39).
Hlatky M A, “Evaluation Of Chest Pain In The Emergency Department,” N. Eng. J. Med. December 1997, 337(23): 1687-1689, reports that after patients in the emergency department having clear-cut acute myocardial infarction have been identified, the remaining patients are more difficult to sort out; that symptoms suggestive of myocardial ischemia at rest that last more than 15 minutes indicate a relatively high short-term risk, probably because of their association with ruptured coronary plaque; that further tests used for patients include those that identify a defect in myocardial perfusion, abnormalities in left ventricular wall motion, or subtle evidence of myocardial necrosis though sensitive assays of intracellular proteins (e.g., CK-MB isoenzyme, myoglobin, troponin T, and troponin I); that even a highly sensitive marker of myocardial necrosis will not necessarily be positive in all patients with acute myocardial ischemia; and that patients who present for the first time with chest pain usually need further tests to establish the likelihood of underlying coronary disease and to guide appropriate therapy.
U.S. Pat. No. 5,756,067 (issued May 26, 1998) notes that tests currently available to measure the risk of developing atherosclerosis include measuring the plasma content of cholesterol, triglycerides, and lipoproteins but that it is clear that these tests are not conclusive because approximately one-half of heart disease due to atherosclerosis occurs in patients with plasma triglycerides and cholesterol within the normal ranges of the population and because angiographic evidence of atherosclerosis has been found in patients with normal lipid levels.
Sasavage N, “Predicting Coronary Artery Disease, New Markers Could Identify Patients At Risk,” Clin. Lab. News March 1998, pages 6-7, suggests that oxidation of low density lipoproteins may render it more atherogenic, that detection of oxidized LDL species faces some technical difficulties, and indicates that coronary artery disease appears to be a multifactorial disease. It also states that those who work in this area agree that development of a new generation of biochemical markers will allow clinicians to better assess patient risk and intervene with treatments to avoid adverse outcomes.
Thus, there is a significant need for a method that with a clinically sufficient degree of diagnostic accuracy can detect coronary artery disease and distinguish between or among its stages.